Treatment of hydrocarbon oils



Jan. 18, 1938. J. D. sl-:GUY

TREATMENT 0F HYDROCARBON OILS Original Filed Nov. 2l, 1950 Patented Jan. 18, 1938 UNHTE 'EES PATE? Jean Delattre Seguy, mesne assignments, Company, Ware Application November 21 Renewed M 4 Claims.

This invention relates particularly to the conversion of hydrocarbon oils of relatively highboiling point into substantial quantities of hydrocarbon oils of lower boiling point such as oils suitable for use as fuel for internal combustion engines.

In one embodiment, the process of theinvention pertains to a method vof operation allowing the use of charging stocks of various chemical characteristics and boiling point ranges, and a method of producing, by primary distillation, charging stocks amenable to conversion in the liquid or liquid-vapor'phase and other charging stocks suitable for treatment in substantially the vapor phase.

The invention also provides a process whereby undesirable reactions may be inhibited during the vapor phase treatment by the use of controllable cooling, as Will be hereinafter described, which results in the production of hydrocarbons, of motor fuel boiling point range, of more desirable characteristics and higher yields of the same than are normal to most cranking operations with less coke and gas formation.

In a preferred embodiment of the process of the present invention a charging stock, typied by a topped crude containing substantially no hydrocarbons Within the boiling point range of motor fuel, is fed in heat exchanging relationship either to the fractionator, in which substantial condensation of the products of the cracking reactions is being eieoted, or, alternately, in heat exchanging relationship with the products from the vapor phase cracking zone with the object of stopping the reaction of said products short of the formation of undesirable products by cooling below a certain critical temperature. The portions condensing as liquid are pumped to a heater in which sufficient heat is supplied'to enable a rough separation, without substantial cracking, into a liquid residue more suitable for cracking in the liquid or liquid-vapor phase and into a mixture of vapors more suitable for cracking under vapor phase conditions.

As a particular example of the operation of the process of the present invention, reference is made to the accompanying drawing, which shows diagrammatically a form of apparatus suitable for conducting the operations involved.

Topped crude may be taken by pump 3 from line I, controlled by valve 2 and pumped through line 4, the flow from which may be divided by the manipulation of valves 6 and 8 controlling the inlet into lines 5 and 'l respectively, to admit this relatively heavy feed either into iractionator Chicago, Ill., assignor, by to Universal Oil Products Chicago, Ill., a corporation of Dela- 1930, Serial No. 497,134 ay 23, 1936 (Cl. ISG-) 34 or into cooler and separator 6| or partially to both. Line 1 is manifolded to provide valved lines A, B and C, at various levels to provide inlets for controlling the cooling of the vapor phase reaction products in the manner desired. The 5 reflux condensate from fractionator 342 is released through line 9 and valve l0 to pump l5 and similarly all or a portion of the unvaporized oil and condensate in the chamber 6| may be released through line H and valve l2 to line 9, l0 and thence through valve l0 to pump l5, provision being made for the withdrawal of the remainder from the system, if desired, through line I3, controlled by valve lil.

Pump I5 pumps the mixture of reflux condenl5 sate and unvaporized charging stock from fractionator 34 and chamber 6l through line i6, controlled by valve l1, to heating element I1 suitably disposed in furnace D. Heat is supplied to the oil under pressures of approximate- 0 ly to 150 pounds per sq. in., more er less, to raise the outlet temperature to some point within the range of temperatures needed to separate liquid-vapor phase and vapor phase charging stocks after release of the heated oil into sep- 2- arator 20 through line I8, controlled by valve I9. Suitable temperatures may fall within the range of G50-850 F., more or less.

Liquid residue from separator 20 is released through line 2l, and valve 22, to pump 23 which 30 discharges through line 24 containing valve 25 into heating element 25, located in a suitable furnace E. Heat is supplied to the oil in heating element 26 under pressures of approximately 200 to 1000 pounds per square inch, more or less, 35 to raise the temperature of the cracked products leaving the heater coil to temperatures within the range of approximately 840 to 900 F., more or less. These products are then discharged into reaction chamber 20 through line 27, controlled 40 by valve 28. Depending upon the severity of the conditions imposed in heating element 26 the products of the reaction in chamber 29 may be principally vapors of hydrocarbons within the boiling point range of motor fuel and highly car- 45 bonaceous semi-solid material resembling coke or may be of a nature more resembling a synthetic crude oil of continuous boiling point range, in which case mo-re or less Viscous residuum is withdrawn in liquid form through line 30, con- 50 trolled by valve 3l.

The vapors from reaction chamber 29 pass through line 32, controlled by valve 33, into fractionator 34. The vapors from separator 2!! pass through line 35 and Valve 36 to a pump 3l which 55 discharges through line 38 and valve 39 into heater coil 40 suitably disposed in furnace F in which heat is supplied to crack the vapors, ternperatures and pressures being employed as may be found most suitable to the chemical nature of the vapors, thetemperature range being approximately 1000 to 1300 F., and the pressures preferably somewhat lower than those employed in the liquid or liquid-Vapor phase reaction effected in coil 26. In some cases it has been found advantageous to maintain temperatures at the exit of heater coil 4U approximately the upper limit of the range mentioned and after discharge through line 4| and valve 42 to `separator 6| admit cold feed at one or more levels so as to quickly cool the products and inhibit undesirable side reactions. The vapors from chamber 6| pass through line 44, controlled by Valve 45 into fractionator 34 which effects separation of hydrocarbons of desired boiling point range from the cracked vapors from both the liquid-vapor and the Vapor phase zones.

Vapors from fractionator 34 pass into line 45, through valve 41 into condenser 48 and the condensed and cooled products pass through line 49 and valve 50 into receiver 5i. Fixed gases in receiver 5| may be withdrawn to suitable storage through line 52, controlled by valve 53, and the liquid products `may be withdrawn through line 54, controlled by valve 55. To assist in the control of the boiling point range of the vaporsY issuing from fractionator 34 pump 58 may withdraw a suitable portion of the liquid Vproduct from rel ,ceiver 5l through line 62, and Valve 63, and/or may, if desired, draw through line l', controlled by valve 2', special distillates from an extraneous source and may discharge either or both of these oils through line 59, controlled by valve 60, into the top of the fractionator 34.

As an example of the results obtained by operation ofthe process of the present invention, a 24.8 A. P. I. gravity Mid-Continent topped crude was used as raw oil charging stock. The crude from which this was obtained was 37.2 A. P. I. gravity and approximate analysis showed the following constitutents: Y

55 A. P. I. gravity gasoline 35%, 40 A. P. I. gravity kerosene distillate 10%, 35 A. P. I gravity gas oil 20% and 24.8 A. P. I. gravity residuum 35%. The topped crude was fed in the ratio of 2 parts to fractionator 34 and 1 part to reaction chamber 6I, pump l5 taking the reflux'and unvaporized charging stock from both the fractionator and the reaction chamber and feeding the oils to heating element Il as combined feed. Y Suflicient pressure was Vmaintained on separator 20 to enable 100 pounds to be carried'at the exit of heating element 4d. By maintaining a temperature of approximately 750 F. at the outlet of heating element Il" the topped crude was separated into approximately 63.5% of 20 gravity residuum l which was crackedin heating element 26 and 36.5% of 35 gravity stock cracked as vapors in heating element 4D. The temperature maintained at the exit of heating element 26 Was approximately 910 F. and the pressure ron reaction chamber 29 was about 150 Ypounds per square inch, this pressure being released by use of valve 53 to approximately 100 pounds per square inch in fraotionator 34. The pressure,` employed in chamber 5I was approximately 100 pounds per square inch, and the temperature at the outlet to heating element 40 was held at between 1050 and 1075* F. The portion of the raw oil feed diverted into chamber 6l from line 'l served to reduce the temperature therein to a mean oi 900 F., the temperature of the vapors leaving the chamber through line 44 being as low as 850 F.

Test samples indicated that the cracking of the residuum in heating element 26 produced 55% of gasoline, 15% of gas and 30% of heavy asphalt stock. From the cracking of the vapors in heating element 40 there was produced on a basis of the oil charged to this element 65% of gasoline, 20% of gas and 15% of tarry liquid which could be lused Aas fuel oil. The overall-yields from the process were 58.6%of 55 gravity gasoline with a benzol equivalent of 65%, 26.4% of asphaltic residuum With a specific gravity of 1.084 and 15% of gas which was equivalent to a yield of 700 cubic feet per barrel of topped crude charged to the process. By the use of high temperatures inV heating element 26 and reduced temperatures in chamber 6i the carbon produced was kept at a negligible value. Y y

It will be obvious from the preceding description that a process has been disclosed which permits of considerable latitude in operation and the use o1" very accurate control of the principal factors affecting cracking-reactions, namely,rthe nature of the oils to be cracked, temperature, pressure and the time of reaction.

I claim as my invention: w l

r1. A hydrocarbon oil cracking process which comprises heating the oil to distillation temperature in a primary heating zone and separating the same into vapors and unvaporized oil, passing the unvaporized oil toa cracking zone and subjecting the same therein to cracking temperature under sufficient pressure to maintain a substantial portion thereof in liquid phase, passing said vapors, without prior condensation and unadmixed with vapors formed in said cracking zone, toa second cracking Zone and cracking the sametherein in the vapor phase by heating to higher temperature than the unvaporized oil, removing the vapor phase cracked vapors from said second Zone and promptly cooling the same by direct contact With a cooling medium, removing vapors fromthe first-mentioned cracking Zone and combining the same with the cooled vapor phase cracked vapors, dephlegmating the combined vapors and returning resultant reux condensate to the primary heating zone, and finally condensing the dephlegmated vapors.

2. A hydrocarbon oil cracking process which comprises heating the oil to distillation temperature in a primary heating Zone and separating the same into vapors and unvaporized oil, passing the unvaporize'd oil to a cracking zone and subjecting the same therein to cracking temperature under sufficient pressure to maintain a substantial portion thereof Vin liquid phase, passing said vapors, without prior condensation and unadmixed with vapors formed in said cracking Zone, to a second cracking zone and cracking the same therein in the vapor phase by heating to higher temperature than the unvaporized oil, removing the vapor phase cracked vaporsfrom said second zone and promptly cooling the same by direct contact with charging oil for the process, supplying the unvaporized portion of the charging oil to the primary heating Zone, removing vapors from the first-mentioned cracking zone and combining the same with'the cooled vapor phase cracked vapors, dephlegmating the combined vapors and returning resultant reflux condensate to the primary heating zone, and finally condensing the dephlegmated vapor.

3. A hydrocarbon oil cracking process which comprises heating the oil to distillation temperature in a primary heating zone and separating the same into vapors and unvaporized oil, passing the unvaporized oil to a cracking zone and cracking the same therein out of contact with said vapors under sufficient pressure to maintain a substantial portion thereof in liquid phase, thereby forming additional vapors, passing first-named vapors, Without prior condensation and unadmixed with vapors formed in said cracking zone, to a second cracking zone and cracking the same therein in the vapor phase by heating to higher temperature than the unvaporized oil, removing the vapor phase cracked vapors from said second zone and promptly cooling the same by direct contact with a cooling medium, combining the cooled vapor phase cracked vapors with said additional vapors and dephlegmating the resultant mixture to condense insuiiciently cracked fractions thereof, and finally condensing the dephlegmated vapors.

4. A conversion process which comprises heating hydrocarbon oil to distillation temperature in a primary heating zone, separating resultant vapors from unvaporized oil and cracking the former in vapor phase in a cracking zone, independently cracking the unvaporized oil in a second cracking zone at lower temperature than said vapors and under suicient pressure to maintain a substantial portion thereof in liquid phase, removing the vapor phase cracked vapors from the first-named cracking zone and promptly cooling the same by direct contact with fresh charging oil for the process thereby vaporizing portions of the charging oil, removing vapors from said second cracking zone and combining the same with the commingled charging oil vapors and cooled vapor phase cracked vapors, fractionating the resultant mixture to condense insufciently cracked fractions thereof, supplying reux condensate thus formed to the primary heating zone, and nally condensing the fractionated vapors.

JEAN DELATTRE SEGUY. 

